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H. D. JAMES Jan. 17, 1928.

SWITCH Drizinal Filed Feb. 20. 920

INVENTOR Henry 0 James. BY

ATTbRNEY Reissues] Jan. 17,1928.

STATES invention relates to switches and it has ar icular relation to electromagneticall{ rable switches of the so-called .loc 0113 which close only when the '1 ciirrenttraversing a selected circuitis below a" "fredetermined 'value. s e ob'ect of my inventionis to provide a switch at e character indicated above in whi hthe eifectiveness of the means tor actiititlng 'the switch to its closed position shall be im: during the closing movement. ,j lh v, e o ration of electromagnetically operable switches in which opposing forces are 'aerted upon the movable members, the force tending to close" a switch at the nstant of the predominance of that force 1s only slightly greater than the opposmg force, since the closing movement is imtlated at that "instant. It is obvious, therefore, that thdclosing movement is efiected while the resultant force exerted upon the movable lement of the switch is materially less than the normal iorce exerted b t e closmg It occurs frequent y that such switches close slowl and that the contact m mbers do not maze firm engagement.

a switch constructed in accordance w t 1 invention, the closing movement of the switch, occurs when the force tending, to

the switch predominates over the opposin v ierce During the closing movement, or

so stantially concurrently with the engagement of the contact members, 8113.11 ap between two relatively movable mem time: the switch is decreased to correspondingly decrease the reluctance of the magnetic circuit for, effecting the closmg of the switch. The efiectiveness of the force exerted by the actuating coil of the switch isithereby materially increased prior to or concurrently with the actual engagement of the contact members. This arrangement efiects; 01.. more positive operation of the switch the result is to prolong the life oil-liev cfojacting 'contact members by reason 0 ftheir'yfirin engagement;

H Imthe accompanying drawing, Fig. 1 1s a side view, partially in elevation andpartiallfifi section of 'a switch embodying my 1 Figs. 2 and 3 are news of details;

. and are diagrammatic views of t R 16,851 PATENT ounce.)

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{diam 'ilal maam, dated Iarch' menisci-m1 Ho. 860,115,fl1ed February 20, man. Application for reissue filed June as, 1927. Serial No. 202,420.

circuits and apparatus embodying a lurality of switches of the types shown in i 1. Referring to Figs. 1,2 and 3, the plate 1 of suitable insulating material supports a stationary contact member 2. A movable contact member 3 is pivotally supported by and yieldingly connected to a movable arm 4 that is, in turn, pivotally sup orted at 5 by a stationary member 6. As est shown in Fig. 2, the arm 4 is pro.- vided with an opening! which materlally reduces the cross-sectional area of the arm and correspondingly increases the reluctance of a. magnetic circuit comprising this 'memher. The movable "arm 4 constitutes an armature member for an electromagnet 8 comprising a shunt-connected coil 9 and a core member 10. The armature member 4 is provided with an extended portion 12 or tail piece of non-magnetic-material which engages" the member 6 to limit the outward movement of the member 4.

'A member 13, the details of which are shown in Fig. 3, andwhich is pivotally supported at 5, is provided with an armature member 14 that is adjustably connected h thereto. The member 13 is provided with an arm 15 which coacts with 'the arm 4 to bridge the opening 7 under conditions to be later described. The member 13 is provided, also, with an arm 16 which coacts with the extension 1.2 of the armature member 4 to limit the relative movements of the arms 4 and 13. The armature member 14 and its connected parts are controlled by an electromagnet 17 which comprises a coil 18 and a core member 19. The coil 18 is so connected that it has series characteristics, that is, it is responsive to the values of the current traversmg the motor circuit.

The switch is normally in its open tion. The coil 9, which may be termed the closing coil is energized to a substantially constant degree and the electromagnet' 8 tends to efiect the engagement of the rela tively movablecontact members 2 and 3. The coil 18, or lockout coil is connected either in series with the motor or in shunt relation to a portion of the starting resistor in such manner as to be energized in accordance with the value of the current travering the motor circuit. The force exerted by the Wmignet 1r tending to the switch ni e; w e n W the motor circuit. As well knomthe'value v w": I V maybe assu u -u that the respective coils I of-jthe switch are elect-rically connected in y position. The electromagnet 8 exerts a sub- {Istentially constant force to move the tnre 4 to its closed position. Kuhn-magnetic circuit of the electropomprises,the core member 10, arripe-member a, and supporting member fi gAs grevionsly statedin connection with the dficription of-thestructural details of 8 the Witeh the armature member 4 is of ree d e rehwtancenft ms-in magnetic circuit is accord- 5A leakge the flux of the electro- EQ f 8 mcludes(.tlle.amatm'emember 4, theiair gap between the armature member aramlthe arm 15 the armrl5, and supporta f 6.. flux traversingtheloakjage path tends. to close the-arr gap between i? alfiq'flf'lmbul'fi number-=4 and, the arm 15 but F ten cy is 'mby theeforce 0f 6t 7 the value of current traversing the series coil l8g fallato-S'uch value that the I F iorce-mrertadby tln 8 predominhteeover that. the u u i7, '1 the armature mkis actuated toward its elosed nsitionby airelativety weak force of mzcbmovement, the j a; op are nearly balanced. The v heyever, by reason of. ';h oftheairgapbetween the core r 10 and the arma- L. tare her 4, while.the force exerted by a the loekout y-rea- W 19i of the; corre- :Hu .4 p, h I a oi the movable member} to ill t Ra t; Ie wx n m '1 inc. i y are); An increased force a ng tends-to efl'ect relative movement 'of t e 2'- 1 apmz-iimndnrmatare 4 m close the i b t ee -P m rgm tsu- I hie; Emm t with, the mte 2 and 3 and theactua- *tignofiktlremovable member 4 toitselosed 5 15 isaotuat d i-q' the armature member 4 no -..e;-mni 1-7- is the arm 15 to flgmlly, t mtanee of the mmn e cireuitandthereby thatthe 1in held in its closed, posi bye that. is 1 materially stronger that exerted upon it its closing of the current decreases "i "9% s 9' the manner d mrrhedabove; it m be a v suinedffiirther, that tliesrvitch isin'lts open y ate in switch 28and they are accordingly sister section.

movemezt. The closing force is alsc; tihn W bi Jeanne. e fict'lhfitflle "refativ trdfithe armature member 4 and arm 15 operates to increase the air. gap between the armature M1,. :19,

m?net 17. t will be readily agipreciated that the arrant yherehy e null of the closing electii'oma is material yincreased at the instant o engagement of the contact memhere has the imporant advantage of effecting engagement and insuring that the movable elements of the. remain in their respective closed The life of the contact members' is increased since this arrangement removes thef possibility of the separation'ofthe con memhers because of the recoil rqm the impact of their-engagement and eliminates the arcing which may resultfrqm such sep'a--- A ratl' v. H -Reference may no w be had 4 in which isillustrated a system embodying an electric motor and a plurality of constructed in, accordance with my invention. An electric motor21 having an armaand ajshunt field magnet winding 23 is supplied with'ener from line conductors 24-and 25. A see JOHBI starting resistor; 26'is'controlled by a series of successively operable switches 27, 28 and 29 of the lockout such as are shown in Figs. 1,2- and}; an ashave been described in detail ye. Similar numerals are employed to designate parts corresponding to those of the switch of F i5. 1. Upon the closing of the motor circuit by anisuitfa bl'e means (not shown) a relatii e- 1y eavycurren't traverses the main circuit incltidingthe resistor 26. Theshunt'closi coil 9 0 the syvitch27, which is connecte' across. theline. is Subjected to line voltage. It, will" be noted, however, that the closing coils 99f switches 28 and 29 have onetermlnal connected to intermediate points. of the starting resistor 26 the alpplied volta is accordingly less: than me voltage.

arr "ement insures that the Switches ghe desired 7 ue'nce. The series lockoutcoils ofeach of e several switchesv I are. connected in shunt relation to that see tion Qfjlffi resistor 26 that is controlled by eni g'izerl an 'acoordance with the; value of the current traversi the motor. circuit asmeasure'd by the drop in potential across the repredeter- 1s adapt- 'lll) when the current falls to the value at which the switch '27 a; to" operate, the armature member 4 and More moved toward their-closed the arm asdscrihedjhove In connection electrothe switch ofFig. 1. The engagement 4 of contact members 2 and 3 closes a shunt ,4 circuit for the corresponding section of the starting resistor 26.

- The shunting of the resistor section rates to connect the closing coil 9 of switch 28 directly across the line and thereby subject it to full line voltage. When the rush connection with switch 27.

tive closing coils are, therefore, entirely unopposed with the exception of the force of gravity tending to open the switches.

The system illustrated in Fig. diflers from that of Fig. 4 in that the series lockout coils arerespectively connected in series with the several resistor sections30 and the armature of the motor. The ,shunt closing coils are connected by an arrangement that is the uivalent of that of the system of Fig. 4. e operation of the system diflers in no material res ect from that of the sys tem of Fig. 4 and a detailed description is omitted as being unnecessary to a complete understanding of this portion of my invention. Y

The many advantages of lockout switches constructed in accordance with my invention, certain of which have been previously fully set forth, will be appreciated by those skilled in the art to which my invention appertains.

I claim as my invention: a 1. The combination with a pair of relatively movable coacting contact members, of a movable magnetizable member operative- 1y connected to one of the contact members,

a winding adapted to normally exert a closing force on the magnetizable member, a'second magnetizable member connected to the first named magnetizable member and movable relatively thereto, a winding adapted to normally exert a force on the second magnetizable member to restrain both members, and means automatically movable to reduce the reluctance of the magnetic circuit through the first named magnetlzable member when the magnetic force exerted thereon exceeds the magnetic force exerted upon the said second magnetizable member.

2. The combination with a pair of relatively movable coactin contact members, of

a movable magnetizab e member operatively connected to one of the contact members, a winding adapted to normally exert a closing force on the magnetizable member, a second magnetizable member connected to the first named magnetizable'member and movable relatively thereto, a winding adapted to normally exert a force on the second magnetizable member in opposition to force exerted thereon through the first magnetizable member, and means controlled by the second named magnetizable member for reducing the reluctance of the ma etic circuit through the first named magnetlzable member when the magnetic force exerted thereon exceeds the magnetic force exerted upon said second magnetizablemember.

3. The combination with a pair of coacting contact members and a movable member operatively connected to one of said contact members, said member having a. magnetizable portion of restricted cross-sectional area, of a second movable member having a magnetizable portion adapted to coact with the other ma netic means or actuating the first movable member, and electromagnetic means operable, when energized above apredetermlned degree, to maintain the separation of said magnetizable rtions.

4. The com ination with a pair ,of coacting contact members and a movable member operatively connected to one of said contact members, said member having a magnetizable portion of restricted cross-sectional area, of a second movable member havin a magnetizable portion adapted to coact wlth the other ma etizable portion. electromagnetic means. or actuating the first movable member, and electromagnetic means operable when energized above a predetermined degree, to maintain the separation of said magnetizable portions and, when energized below a predetermined degree, to permit relative movement of said magnetizable portions to increase the efi'ectiveness of the first electromagnetic means.

In testimony whereof, I have hereunto subscribed my name this 20th day of June,

HENRY D. JAMES.

etizable portion, electromag- 

